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Biomedical subjects

J K Howard

Publications and source records attributed to J K Howard.

At least 37 records · Page 2Linked to original sources
PubMed1986

Case-control study of multiple myeloma and farming.

A previous case-control study which utilised the occupational information available on the New Zealand Cancer Registry found an increased risk of multiple myeloma in agricultural workers consistent with previous findings in the United States. The findings are now presented for the second phase of the study which involved interviewing 76 cases of multiple myeloma (who had been included in the previous study) together with 315 controls with other types of cancer. The previous finding on an excess of farmers in the case group was confirmed by the interview data (odds ratio = 1.7, 95% confidence limits 1.0-2.9, P = 0.04). There were no significant differences between cases and controls regarding potential exposure to phenoxy herbicides or chlorophenols. There were also no significant differences regarding activities involving potential exposure to other agricultural chemicals, although the odds ratio for fencing work, which may involve exposure to arsenic and sodium pentachlorophenate, was 1.6 (95% confidence limits 0.9-2.7, P = 0.11). The odds ratios were significantly elevated for sheep farming (odds ratio = 1.9, 95% confidence limits 1.0-3.6, P = 0.04) and exposure to beef cattle (odds ratio = 1.7, 95% confidence limits 1.0-2.9, P = 0.05). The odds ratio was also elevated for persons reporting a history of hay fever (odds ratio = 1.9, 95% confidence limits 1.0-3.5, P = 0.05). Overall, these findings suggest that the search for the causes of elevated mortality in farmers from multiple myeloma should be directed to potential causes other than pesticide exposure.

Aged↗
PubMed1986

Occupation, social class and male cancer mortality in New Zealand, 1974-78.

Occupational and social class differences in cancer mortality among New Zealand males aged 15-64 are examined for the period 1974-78. Age-standardized cancer mortality rates are presented for the Registrar General's social classes as well as for each of six occupational orders and 79 occupational groups. The rates for specific cancer sites are also presented for each social class and for those occupational groups with significantly elevated relative risks. The findings of the social class analyses were generally consistent with those of recent British studies with mortality from cancer of the liver, larynx, lung, buccal cavity and stomach being particularly high in the lower social classes and mortality from multiple myeloma, malignant melanoma and lymphatic leukaemia being particularly high in the upper social classes. The findings of the occupational group analyses were also generally in line with those of recent British studies and those associations which have been found in British studies and were also present in the New Zealand data are discussed. It is concluded that there are a number of associations which warrant further investigation including: large bowel cancer in woodworkers and printers; bladder cancer in hairdressers and beauticians; and malignant lymphoma in farmers.

Adult↗
PubMed1986

Leukemia among New Zealand agricultural workers. A cancer registry-based study.

Mortality studies have indicated that workers in agriculture and forestry may be at increased risk of leukemia. Findings are reported from a New Zealand Cancer Registry-based case-control study involving 546 male leukemia patients registered during 1979-1983 and aged 20 years or more at time of registration. Controls were also males chosen from the Cancer Registry with four controls per case, matched on age and year of registration. The case group contained an excess of the occupational category involving agriculture and forestry (odds ratio (OR) = 1.24, 95% confidence interval (CI) = 0.95-1.61) with the greatest relative risk being for livestock farmers (OR = 3.00, 95% CI = 1.23-7.32). There was also an excess of electrical workers (OR = 1.72, 95% CI = 0.92-3.20). The agricultural excess was greatest in patients aged 65 years or more at time of registration (OR = 1.29, 95% CI = 0.94-1.78), particularly in patients with acute myeloid leukemia (OR = 1.55, 95% CI = 0.90-2.67) or acute monocytic leukemia OR = 10.38, 95% CI = 1.99-54.29), although the latter excess only involved five cases. Acute myeloid leukemia was also elevated in meat workers (OR = 2.51, 95% CI = 1.19-5.30).

Adult↗
PubMed1986

Non-Hodgkin's lymphoma and exposure to phenoxyherbicides, chlorophenols, fencing work, and meat works employment: a case-control study.

A previous case-control study which used the occupational information available on the New Zealand Cancer Registry found that agricultural workers were at increased risk of developing non-Hodgkin's lymphoma. The findings are now presented for the second phase of the study which entailed interviewing 83 cases of non-Hodgkin's lymphoma registered under code 202 of the International Classification of Diseases together with 168 controls with other types of cancer and 228 general population controls. The findings for the two control groups were similar, and there were no significant differences between cases and controls regarding potential exposure to phenoxy-herbicides (odds ratio = 1.4, 90% confidence limits 0.7-2.5, p = 0.26) or chlorophenols (odds ratio = 1.3, 90% confidence limits 0.6-2.7, p = 0.39). The odds ratio for fencing work, necessitating exposure to several potential risk factors including arsenic and sodium pentachlorophenate was 2.0 (90% confidence limits 1.3-3.0, p = 0.01). The odds ratio for employment in a meat works, necessitating potential exposure to 2, 4, 6-trichlorophenol and zoonotic viruses, was 1.8 (90% confidence limits 1.1-3.1, p = 0.04). There was a significant statistical interaction between the risks associated with these two activities, the odds ratio for involvement in both activities compared with involvement in neither being 5.7 (90% confidence limits 2.3-14.3, p = 0.03).

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1984

Soft tissue sarcoma and exposure to phenoxyherbicides and chlorophenols in New Zealand.

Phenoxyherbicides, including (2,4,5-trichlorophenoxy)acetic acid (CAS: 93-76-5), have been widely used in New Zealand for over 30 years. In the light of Swedish studies reporting an association between exposure to phenoxyherbicides or chlorophenols and soft tissue sarcoma, a case-control study was undertaken that involved interviewing 82 subjects (cases) with soft tissue sarcoma and 92 controls with other types of cancer. For those potentially exposed to phenoxyherbicides for more than 1 day not in the 5 years before cancer registration, the estimate of relative risk was 1.3, with 90% confidence limits of 0.6-2.5. The comparable relative risk estimate for chlorophenol exposure was 1.5, with 90% confidence limits of 0.5-4.5. The discovery of cases in trichlorophenol manufacturing plants in the United States lended support to the Swedish findings, but further studies are needed to conclude whether human exposure to these chemicals truly increases the risk of soft tissue sarcoma.

2,4,5-Trichlorophenoxyacetic Acid↗
PubMed1981

A study of the health of Malaysian plantation workers with particular reference to paraquat spraymen.

Tests of pulmonary function (FVC, FEV1, FEV 1%, and single breath CO diffusion), renal function (serum creatinine and BUN), liver function (serum ALT, AST, and ALKP) and a full haematological screen were performed on 27 paraquat spraymen (mean spraying time 5.3 years; mean individual annual quantity of paraquat handled, 67.2 kg as paraquat ion) and on two control groups. One of the control groups consisted of 24 general plantation workers with minimal exposure to paraquat arising from occasional work in recently sprayed areas, and the second consisted of 23 latex factory workers with no known occupational exposure to paraquat. The results showed no significant differences as a consequence of occupational exposure to paraquat. Long-term paraquat spraying at the concentrations used produced to quantifiable harmful effects on health as measured by the indices selected for this study.

Adult↗
PubMed1979

A clinical survey of paraquat formulation workers.

A group of 18 male Caucasian workers from the United Kingdom and a further group of 18 male mixed race (mainly Malay) workers from Malaysia employed in the formulation of paraquat-based herbicides were examined for evidence of chronic ill health after long-term exposure to paraquat. Clinical records were examined, medical and occupational histories were obtained and a clinical examination, particularly of the skin, was undertaken. Skin rashes, nail damage and epistaxes were encountered by most workers as a result of direct contact of skin and mucous membranes with paraquat. These conditions subsided rapidly and no worker reported any sequelae. There was no clinical evidence of long-term effects on skin, mucous membranes or general health following exposure to paraquat over several years in these workers.

Adult↗
PubMed1978

Interrelationships of glutathione reductase, 5-aminolevulinic acid dehydratase, and free sulfhydryl groups in the erythrocytes of normal and lead-exposed persons.

Blood lead, erythrocyte glutathione reductase (GSSG-R), 5-aminolevulinic acid dehydratase (ALA-D), and free sulfhydryl (SH) groups were measured in normal subjects and in those with occupational exposure to lead. With increasing blood lead concentration the activity of GSSG-R rises and that of ALA-D decreases. There is also a fall in the level of free SH with rising blood lead concentrations. There is a high degree of correlation between these parameters, and it is suggested that the changes represent part of a biological control mechanism to compensate for the reduction of available sulfhydryl groups by lead ions.

Erythrocytes↗